That part doesn't have to be done wirelessly.

It… does. Otherwise the vehicle can’t "power itself from radio waves.” The receiver has to be in the car.

I don't think it would be with tiny amounts of energy you'd get from radio waves.

Correct, but with the scale of power output required to actually do what the post claims it can do, it would be on the order of what happens to commercial windmills when they don’t shut down in high winds.

Then it might be enough to at least use that as a hybrid source of energy, supplementing plugging into the grid.

Remember in the ‘80s when “microwave power stations in orbit beamed down to Earth” was The Future™? Turns out, with the surface area required by the receiver antenna, solar panels (even at the time) could produce about three times the power. It’s just not viable. There are some electric cars today with solar panel roofs (to do just what you’re suggesting), but even then it’s really, truly just a “top up” supplement, not anywhere near capable of powering it indefinitely.